Lie detectors don't work: that's why they're not admissible as legal evidence and why it's illegal to subject private sector job-applicants to polygraph tests.
But public employees aren't so lucky: the polygraph industry intensively lobbies people with hiring power in public sector to institute lie-detector screening; since the targets of this lobbying have all passed polygraphs themselves, they're inclined to think of them as useful tools for sorting the trustworthy from the untrustworthy.
Wired used the Freedom of Information Act to request some pretty massive datasets of polygraph data from the public sector's hiring processes (discovering in the process that polygraph record-keeping is terrible) and analyzed the data, producing a disturbing account of people who are routinely, unfairly accused of grave crimes (bestiality, child porn possession), never tried or convicted, but nevertheless barred from employment. What's more, Wired shows that different polygraph officers are more prone to accusing their subjects of disqualifying crimes.
Data obtained by WIRED showed vast differences in the outcomes of polygraph tests depending on the examiner each candidate faced. Consider another law enforcement agency that uses polygraphs in its employment process: the Washington State Patrol (WSP). Between late October 2011 and the end of April 2017, the WSP conducted 5,746 polygraph tests on potential recruits. This was the largest data set WIRED received, including copious data on both applicants and examiners. While one examiner failed less than 20 percent of candidates, others failed more than half the applicants they screened. And while two examiners disqualified just four people in more than 1,000 applicants for supposedly having sex with animals, one of their colleagues failed more than 10 times as many for bestiality—around one in 20 of all job seekers. The same examiner was also twice as likely as the resthis peers to fail applicants on the grounds of child pornography.
There were no further hearings trials for these supposed crimes, and no jury to convince or judge to adjudicate, just scores of otherwise qualified applicants who would now not become Washington state troopers.
"We don't know which, if any, of the examiners are accurate, but the disparity between them suggests the test is not being used in a way that is at all reliable," says John Allen, a professor of psychology at the University of Arizona. And tests that are not reliable, Allen says, cannot be valid.
The Lie Generator: Inside The Black Mirror World of Polygraph Job Screenings [Mark Harris/Wired]
